Reinforcing cords and belts made therefrom for reinforcing pneumatic tires are well known in the art. A wide variety of materials and configurations have been suggested for utilization in pneumatic tire constructions in an effort to provide reinforcing belts which are thin and light yet demonstrate a high resistance to lateral movement.
U.S. Pat. No. 2,257,646 to Pierce discloses tension elements formed from a flattened core of rubber or similar plastic surrounded by and bound to a wire braid.
U.S. Pat. No. 3,431,962 to Kersker et al. discloses reinforcement elements which comprise a strip of non-circular cross-section having a multiplicity of continuous parallel untwisted filaments adhesively bonded or compacted together. The thickness of the strip is advantageously one-fifth to one-twenty-fifth its width.
U.S. Pat. No. 3,667,529 to Mirtain discloses a single-layer ply structure of metallic wires or strips oriented at a substantial bias angle as an adjunct to a multi-layer belt of textile cord plies oriented substantially circumferentially.
U.S. Pat. No. 3,786,851 to Mirtain et al. discloses a breaker having a plural-layer ply of non-metallic cords oriented at 0.degree. superposed on a plural-layer ply of metallic strips crossed relative to those in the adjacent layer and oriented from 16.degree. to 30.degree. .
U.S. Pat. No. 4,349,063 to Kikuchi et al. discloses a pneumatic radial tire reinforced with steel cords which have a flat or elliptic section. The cords comprise two or three strands, each strand produced by twisting plural filaments, arranged in parallel to form a core about which additional filaments are twisted.
U.S. Pat. No. 4,609,024 to Yatsunami et al. discloses a cord comprising a core of two metallic wires and an outer layer of six metallic wires, all of which have the same diameter.
U.S. Pat. No. 4,733,708 to Kindry et al. discloses a tread reinforcing belt structure of a pneumatic tire having at least one ply of flat steel wire. A radial outward ply of non-metallic cords such as heat shrinkable nylon is disclosed in several embodiments.
Some prior art tires have reinforcing belts including reinforcing cords with round cross-sections. Round cross- section textile cords are most commonly used in applications requiring fuel efficient or other lightweight tires, while steel cords are most commonly used in applications requiring prolonged tread life or other rugged wear tires. Other prior art tires have reinforcing belts including reinforcing monofilament cords with flattened cross-sections that are generally formed from steel. Disadvantages of these steel cords are their weight, which decreases fuel economy, and their stiffness which decreases fatigue performance.